Method and apparatus for manufacturing calender roll filler material and resultant product



United States Patent Lamar A. Moss Milford, New Jersey [21] Appl. No. 688,541

[22] Filed Dec. 6,1967

[45] Patented Oct. 6, 1970 [73] Assignee Riegel Paper Corporation New York, New York a corporation of Delaware [72] inventor [54] METHOD AND APPARATUS FOR MANUFACTURING CALENDER ROLL FILLER MATERIAL AND RESULTANT PRODUCT 13 Claims, 5 Drawing Figs.

Primary Examiner Bernard Stickney Attorney-Mandeville and Schweitzer ABSTRACTi The present invention is directed to a calender roll filler material which is manufactured by fabricating an an nular pad from a pad of paper sheets in which the machine directions of all sheets are coincident and thereafter substantially uniformly orienting the machine direction of each successive sheet with respect to the machine direction of its neighboring sheet. Rapid and uniform orientation of the machine direction of each sheet is effected by the controlled. repeated bending of the annular pad of sheets. Apparatus for manufacturing the new filler material from annular pads includes a mandrel for supporting a pad, the sheets of which are initially aligned with their machine directions coincident; resilient guide fingers for maintaining the annular pad generally transversely of the support mandrel; rubber annular facing discs superimposed at the ends of the pad; a compressible sponge member interposed at the center of the pad and effectively dividing it into a pair of pads; and a pair of rotatable eccentric bending means disposed on opposite sides of the pad and on alternate sides of the longitudinal axis of the mandrel for cyclically bending the pad. The applied bending forces angularly advance the outermost sheets greater amounts than the innermost or centrally disposed sheets immediately adjacent the cushion. The mechanics of the bending are such that the individual annular discs comprising the pad will be uniformly angularlydisplaced or rotated from the outermost portions of the pad to the central portions of the pad, that is to say, the machine directions of the sheets will be uniformly spirally arrayed.

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ATTORNEYS Patented Oct. 6, 1970 3,532,031

Sheet 2 of2 INVENT 44/211 4. 0.5:

ATTO R N EYS METHOD AND APPARATUS FOR MANUFACTURING CALENDER ROLL FILLER MATERIAL AND RESULTANT PRODUCT BACKGROUND OF THE INVENTION Filled supercalendar rolls are well known and widely used in the papermaking industry and typically comprise a metal core upon which a plurality of paper or cloth discs are supported under the compression of end plates. These rolls have resilient outer surfaces which contact the web to be calendered.

Heretofore it has been accepted practice in the manufacture of filled calender rolls to initially produce the filling material in noncircular shapes, such as octagons, for example, by die cutting a pad of paper made from sheets. all of whose major axes" are coincident and defined by the machine direction" of the paper. Machine direction is, of course, the direction of the grain of the paper which is parallel to its forward movement during formation on a paper machine. Hereinafter, for brevity and clarity of description, the expression major axis of the filling material will be used to denote the geometrical, diametral axis of the calender filling material whichis coincident with the machine direction of the sheet from which the filling material was formed. The noncircular calender filling material is then shipped from the paper manufacturersplant to the site of calender roll filling where the standard filling material is placed on the calender roll core in a comparatively loose fashion.

It is well recognized calender roll making practice to eliminate the uniform alignment of the major axes of the filling material from sheet to sheet throughout the length of the roll in order to enhance the characteristics of the finished calender surface. This has been effected heretofore by subjecting the octagonal or otherwise noncircularly shaped filler sheets to the action of air jets to rotate the major axes of the discs randomly about a mandrel prior to cutting a keyway in the randomized filler sheets and placing them on the calender roll shaft. This step is, of course, performed after a hole is formed in the center of a pad of noncircularly shaped filler sheets. Thus, by randomly spinning the plurality of octagonal elements, a nonuniformity, more specifically, a random orientation of the major axes of the tiller material with respect to one another throughout the length of the calender roll will be achieved. The roll is conventionally completed by a turning operation which converts the edges of the randomized octagonal elements into a cylindrical roll surface.

The accepted techniques of the prior art have resulted in substantial waste and unnecessarily high shipping costs. For example, after the octagonal or the conventional sheets of filler material have been randomized on the calender core, it is then necessary to perform an operation to bring the roll into round i.e., turn the outer surfaces of the roll to establish a cylindrical rolling surface. The material that is trimmed away from the octagonal elements in reducing them to annular shape in the calender roll manufacturers plant represents a double waste. In addition to the fact that it is impracticable to salvage any of the trimmed paper, the waste trim will have been subjected to substantial shipping costs.

SUMMARY OF THE PRESENT INVENTION It is the object of the present invention to provide calender roll builders with a new filler material which requires no further orientation, by randomizing or otherwise, at the roll builder's plant. It is a further object of the invention to provide a material which may be shipped at reduced cost per finished calender roll and to provide a filler material in which paper waste is minimized and virtually completely eliminated. The realization of these objectives has resulted in substantial cost savings to both the manufacturer of the filler material and the manufacturer of the finished calender roll.

In accordance with the principles of the present invention, these economic benefits as well as other advantages are realized by preforming pads of sheets of filler material annular discs and thereafter orienting the major (machine direction) axes of successive sheets of calender filler material in the plant of the paper manufacturer rather than in the plant of the roll builder. As will be appreciated, by performing the cutting and orienting operations at the same site, more specifically, forming annular filler discs in the paperrnakers plant, the hereto fore wasted trimmed paper, which in some cases is as much as 50 percent of the original octagonal paper sheets, can be easily handled and carefully preserved free of contamination for subsequent reuse as broke in future runs of calender filler grade paper on nearby paper machines. Additionally, through the techniques to be recited in greater detail hereinafter, the sheet-to-sheet orientation of the new annular calender filler material is carefully controlled and optimized in contrast to the random or haphazard orientation of conventional filler material.

More specifically, the efficacy of the new system is a result of the effects of bending a pad of paper sheets about a radius while generally anchoring the pad. That is to say, the successive sheets of a bent pad are displaced in direct proportion to the difference in bending radius, which difference on a sheetto-sheet basis is represented by the thickness of an individual sheet. Therefore, the sheet-to-sheet displacements will be uniform if the thickness of each sheet in the pad is equal.

While any one of numerous mechanical devices may be employed to bend a paper pad of calender filler discs to uniformly orient the major axes thereof, a most advantageous apparatus for producing the new calender roll filler material includes a smooth surfaced mandrel for supporting a pad of preformed annular calender tings between two opposing eccentric bending rollers. The apparatus further includes a resilient compressible cushion disposed in the center of a pad to be oriented and two flexible rubber sheets generally congruent with the paper discs placed on opposite sides of the paper pad. The eccentrics are disposed on alternate sides of the longitudinal axis of the supporting mandrel, about which mandrel the individual discs are free to rotate as the eccentrics are driven in the same direction. Included in the apparatus are a set of resilient guides which maintain the pad generally transversely of the longitudinal axis of the mandrel.

The eccentrics are synchronously driven in the same direction, e.g.) clockwise, from a position of maximum separation in which the centers of the pad halves remain flat and relaxed to a position of minimum separation in which the pad halves are tightly compressed against the intermediate rubber cushion. In the fully compressed position of the eccentrics, the paper pad is bent into a generally serpentine curve at its central portions, which bending causes one-half of the pad to move to the left and the other half of the pad to move to the right. More specifically and in accordance with the principles of the invention, the absolute movement of each sheet is in direct proportion to its displacement from the center of the pad. That is to say, the outermost sheets of the pad will be displaced angularly the greatest distance, while the innermost sheets will be displaced considerably smaller amounts. However, as an important aspect of the invention, the sheet-tosheet relative angular displacement of the major axes of the filler discs will be uniform from the outermost sheet to the in nerrnost sheet.

As a very important aspect of the invention, the bending eccentrics are rotated at a fairly'rapid rate in order that the frequency of the compression strokes is high enough to maintain the sheets in substantially constant movement. As a still further important aspect of the invention, the bending and gentle slapping actions of the apparatus cause air to be driven into the pad of filler material to provide a lubricating film of air between each successive pair of sheets. The air lubrication aids in smoothing the orientation action of the apparatus and accommodates the free movement of each sheet with respect to the neighboring sheets.

In accordance with another important aspect of the invention, the intermediate sponge rubber cushion greatly contributes to the smooth and continuous orientation action of the apparatus. Additionally, the cushion effects the relative anchoring of the center sheets of the pad to cause angular displacement of half the pad in one direction and angular displacement of the other half of the pad in the opposite direction. Absent an intermediate cushion, the center of an individual paper pad would move haphazardly, and it would be impossible to achieve uniform angular displacement of sheets through the thickness of the pad.

DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, reference should be made to the following drawings, in which: H

FIG. I is a front elevational view of an apparatus embodying the principles of the present invention;

FIG. 2 is a side elevational view of the apparatus of the invention;

FIG. 3 is a top plan view of the apparatus of the invention showing a divided pad of filler material in a relaxed position before orientation;

FIG. 4 is a top plan view of the apparatus of the present invention showing a divided pad of filler material in a fully compressed position during orientation; and

FIG. 5 is a top plan view of the apparatus of the invention showing a divided pad in a relaxed position at the completion of a cycle and showing the uniform sheet-to-sheet angular displacement.

DESCRIPTION OF THE INVENTION Practice of the present invention is simple and efficient. The starting material is a pad P of square sheets of paper which is formed from a web by sheeting apparatus and which pad therefore has a sheet-to-sheet alignment or coincidence of machine direction. The pad is cut into an annular shape by converting equipment in the papermaker's plant. For example, concentric circular dies may be employed to die cut pads of sheets ranging in thickness from /2 to 2 inches into an annulus of predetermined inside and outside diameters. Alternatively and preferably, the pad of aligned sheets (in terms of the major axis or machine direction) may be formed into an annulus by the use of turning equipment. Regardless of the method of converting the rectangular pad into an annulus and as a most important aspect of the invention, all the waste at this stage of the operation, which may be as much as 50 percent of the original paper, may be carefully stored for use as broke in future runs of calender paper grade material. It should be understood that the individual discs comprising the annular pads of calender filling material at this stage have their major axes substantially coincident. That is to say, the sheets of the pad are in the same orientation as when they emerged from the sheeting machine.

In accordance with the invention, the unoriented annular pads are then subjected to a controlled bending action to uniformly orient the major axes of the pad. As will be understood, the sheet-to-sheet, uniform, mutual angular displacement of the major axes will provide a more uniform calender roll surface then has heretofore been available. This uniform and controlled orientation of the annular pads is effected by a new pad bending apparatus 9.

Referring to FIG. I, the new apparatus 9 is supported on a machine column 10 and generally includes a bending mechanism 11 disposed above a supporting mandrel 12 for the pad P of annular calender filler material. Advantageously, the mandrel 12 is provided with a smooth surface 14 to accommodate differential slippage of the sheets of the pad.

To facilitate the loading and unloading of the pads P, the elevation of the mandrel is selectively adjustable along the column 10. Advantageously, a slide bracket 16, may be used to position the mandrel 12 well below the mechanism or to lock the mandrel in the position illustrated. The bending mechanism is supported above the mandrel 12 on a frame 18. which, itself, is cantilevered to the column 10 through a suitable bracket 20.

In accordance with the principlesof the invention, a pair of crank arms or eccentrics 21,22 are supported on shafts 25, 26 depending from the housing 18 on opposite sides of the pad P of calender filler material and on alternate sides of the vertical center line of the mandrel 12, as shown in FIG. 2. Advantageously, when the arms 21, 22 are colinear (FIG. 4), they are at an angle of 3060 with the general plane of the pad. The actual bending forces are applied to the pad through free wheeling roller cam members 23, 24, respectively, which are supported by stub shafts (not shown) projecting from the ends of the eccentric arms 21, 22. The eccentric shafts 25, 26 mount spur gears 27, 28 through which they are driven by a larger spur gear 29. Motive power for the gear 29 is derived from a sheave 31 which is mounted on a common shaft 41 with the gear 29. The bending apparatus is powered by an air motor 43 whose output is transmitted to the sheave 31 through a sheave 42 and drive belt 30, as shown in FIG. 1.

As an important aspect of the invention, a rubber sponge cushion 32 is supported by rods 15 from the frame 18 in a plane which is located intermediately of the two shafts 25, 26, as shown in the drawings. Advantageously, the cushion comprises a sponge core covered with cloth impregnated with an antistatic agent to minimize friction and to prevent the generation of static electricity as the pad is oriented. The apparatus also includes spring guide elements 33, 34. shown in FIGS. 3 5, which are disposed on opposite sides of the pad and which are intended to keep the pad generally transverse of the mandrel, as shown. Additionally, the apparatus includes rubber facing sheets 35, 36 which are superimposed over the ends ofthe pad, as shown in the drawings.

Operation of the new device is extremely simple and highly effective. An annular pad of calender paper ranging in thickness from approximately two to four inches is divided and placed on the mandrel 14 straddling the resilient central cushion 32 with the annular rubber facing sheets 35 and 36 placed at ends of the divided pad. As should be understood, the mandrel 12 is raised and lowered along the column 10 for the purposes of loading and unloading the apparatus. At this initial stage, the major axes of all of the individual discs of filler material are aligned, and the pad may be said to be unoriented. In FIG. 3, for the purposes of illustration, a reference guide line L has been scribed vertically along the edge of the divided pad of filler sheets to indicate the coincidence of the major axes of the sheets and the unoriented condition of the pad.

Thereafter, the bending apparatus is started and the bending rollers 23, 24 are both rotated clockwise, as shown in FIG. 3, from an open or pad relaxed" position toward a closed or pad compressed" position. As the rollers engage the opposite rubber annular discs 35, 36, they progressively compress the divided pad into an S or serpentine shape at central portions thereof and as shown best in FIG. 4. In accordance with the principles of the invention, the nature of the bending of the pad will cause the outermost sheets thereof to be angularly displaced a relatively large amount in comparison with the innermost sheets, while the intermediate sheets will be uniformly, gradually displaced therebetween. As explained hereinabove, the outermost sheets are bent about a radius comprised of the total thicknesses of all the sheets from the center of the pad outward, while the sheets increasingly nearer to the cushion 32 are all bent about increasingly smaller radii. As the rollers repeatedly continue to engage and compress the pad into an S shape once during each complete revolution thereof, the sheets comprising the pad will be gradually and increasingly, angularly displaced with respect to one another, as indicated by the slope and increased length of the reference line L in FIGS. 4 and 5.

With the bending rollers cycled at a reasonably high speed, e.g., 200 rpm, the sheets of the pads will be kept in substantially constant and uniform motion, with one half of the pad moving clockwise and the other half of the pad moving counterclockwise. The rotation of the eccentrics carrying the bending rollers at sufficiently high rates to maintain the frequency of the compression strokes high enough to keep the sheets in substantially constant movement represents an important principle of the invention. At these speeds, the bending and gentle slapping actions of the apparatus cause air to be driven into the pad of filler material and thus provide a lubricating film of air between each successive pair of sheets. As will be appreciated, this type of lubrication aids in smoothing the orientation action of the apparatus and accommodates the free movement of each sheet of the pad with respect to adjacent sheets,

It ,should be understood that the intermediate sponge cushion 32 greatly contributes to the smooth and continuous orientation action of the new apparatus. The cushion 32 provides a relative anchoring of the center sheets of the pad which allows the bidirectional angular displacement of the pad halves. Moreover, were the cushion 32 to be omitted, the center of an individual pad would move irregularly, and it would be impossible to achieve uniform angular displacement of sheets through the thickness of the pad.

The manufacture of the new material is completed by cycling the apparatus a sufficient number of times to achieve a predetermined desired orientation of the sheets of filler material. When the eccentric rollers are operated at speeds of approximately 200 rpm, sheet-to-sheet displacements of to may be achieved in approximately one minute. As will be understood, the operating parameters of the bending apparatus may be varied to provide a greater or lesser sheet-tosheet angular displacement, as desired or found necessary for a particular application.

It will be appreciated that the method, apparatus and resultant product of the present invention provide substantial economics for both the papermaker and calender roll builder in the manufacture of filled calender rolls. For example, the trimmed excess paper material which has heretofore been unsalvageable and wasted may be practicably and easily reused as broke when the annular cutting operation is performed in the papermakers plant. As should be understood, heretofore it has been impracticable to perform this step before the filler material was oriented. Thus, the cutting of the filler discs had to be done away from the papermaking site and at locations where the trimmed waste could not be properly preserved for reuse as broke. Moreover, the unsalvageable waste was subjected to shipping costs which have been completely eliminated by the practice of the invention. As a corollary benefit, the calender roll maker no longer is required to perform randomizing and trimming operations in his plant, thus saving substantial labor costs. Additionally, the new, uniformly oriented calender filler material, itself, represents a significant improvement over the randomly and haphazardly oriented filler discs that have been used heretofore in the manufacture of filled calender rolls. Furthermore, the unique pad bending apparatus achieves the desired uniform orientation in a quick and efficient manner.

It should be understood that the specific method of orientation, the new bending apparatus for effecting the same, and the resultant oriented calender roll filler material herein illustrated and described are intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

lclaim:

l. A method of manufacturing calender roll filler material from an aligned rectangular pad of sheets having major axes coincident with the machine direction of said sheets, comprisa. forming an annular pad from said aligned pad;

b. supporting said aligned pad at inner diameter portions thereof; and

c. applying rotational forces to said aligned pad to change said alignment to a predetermined orientation in which the major axes of each successive sheet is substantially uniformly angularly displaced from the major axis of the immediately preceding sheet.

2. The method ofclaim l. in which:

a. said uniform angular displacement of successive sheets is related to the thickness of said pad in a manner whereby said major axes are generally spirally arrayed through said pad.

. The method of claim 1. in which:

. said aligned pad is formed by die cutting techniques.

. The method of claim 1. in which:

. said aligned pad is formed by turning techniques.

. The method of claim 1. in which:

said rotational forces are induced in said aligned pad by bending the same.

6. A method of manufacturing calender roll filler material,

comprising:

a. forming a rectangular pad of sheets which are aligned in the machine direction,

b. converting said aligned pad into an annular pad;

c. supporting said annular pad on a mandrel with said pad divided by a compressible element;

(1. said pad, when unstressed, being flat and perpendicular to the longitudinal axis of said mandrel;

e. applying orientation forces to opposite sides of said aligned pad at sites on opposite sides of the longitudinal axis of the mandrel to compress said pad while bending central portions of said pad from a flat to a generally S- shaped configuration with each sheet being bent about a radius of different length, the bending radius varying from sheet to sheet by an amount substantially uniform and substantially equal to the thickness of each of said sheets;

. removing said orientation forces from said pad and allowing said pad to return to a flat configuration in which the major axes of successive ones of said sheets are substantially uniformly angularly displaced; and g. cyclically reapplying and removing said orientation forces to increase the uniform angular displacements of successive ones of said sheets.

7. Apparatus for reorienting annular pads of discs having their major axes in alignment, comprising:

a. means for supporting said pads at inner diameter portions thereof; and

b. means for applying rotational forces to said aligned pads to change said alignment to a predetermined orientation in which the major axis of each successive disc is substantially uniformly angularly displaced from the major axis of the immediately preceding disc.

8. Apparatus for reorienting an annular pad of discs, comprising:

a. support means for holding said pad generally in a flat condition;

b. bending means disposed above said support means and including an eccentric member;

c. cushion means adapted to engage a central portion of said pad and adapted to be compressed by the action of said eccentric;

d. flexible surface sheet means adapted to engage an endmost disc of said pad; and

e. drive means for rotating said eccentric into and out of contact with said surfacing sheet means.

. The apparatus of claim 8, in which:

said support means includes a smooth-surfaced mandrel;

and

b. said eccentric means includes a pair of crank arms mounting free wheeling rollers for engaging said surface sheet means.

10. The apparatus of claim 9. in which:

a. said surface sheet means comprises a pair of rubber discs generally congruent with the pad to be oriented.

11. The apparatus of claim 8, in which:

a. said cushion includes a sponge core covered by a fabric impregnated with an anti-static agent.

12. The apparatus of claim 8, which includes:

a. means for varying the spaced relationships of said bendt urm-ni oa a. said drive means is adapted to rotate said eccentric means at predetermined speeds sufficient to maintain the discs of pad in substantially constant motion. 

